Dynamo.



H; EITNER.

DYNAMO.

APPLICATION FILED 1AN.23.1915.

1 ,283,534. Patented Nov. 5, 1918.

ZE-EQ E91 IIHHI H. LEITNER.

DYNAMO.

APPLlcATloN HLED 1AN.23.1915.

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UNITED sTA'rEs PATENT OFFICE,

HENRY LEITNER', OF TUNBRIDGE WELLS, ENGLAND.

DYNAMO.

To all u'kom it may 0072087121:

Be it known that I, HENRY LITNER, a subject of t-he Kingvof Great Britam, reslding at Montacute House, 45 Broadwater Down, Tunbridge T'Vells, Kent, England, have invented new and useful improvements in or Relating to Dynamos, of which the following is a specification.

My invention relates to means for regulating the output of dynamo machines designed tobe driven at variable speeds. ln such machines when used in conjunction with accumulators for train lighting and the like, it is well known that it is advisable gradually to reduce the output of the machine as the voltage of the battery rises on charge, so that when the battery is fully charged the charging current is reduced 'practically to zero or to a very low value,

It is also advantageous to limit thevoltage of the machine when the lamps are in circuit, so that it may not rise much above the normalflamp voltage. It has been common practice to reduce the output of such machines by introducing a resistance or resistances into the shunt field circuit, or, in general, by diminishing the field flux by reducing the -current in the exciting coils. This method, however, is not entirely satisfactory because its action is to acertain extent interfered with by the characteristics imposed upon the machine due to the necessity of compensation for variations in speed.

Now, according to my invention I dispense wholly or partially with the necessity of introducing resistance into the field circuit or into any equivalent circuit, and in lieu thereof I provide the dynamo with an additional series winding, in series with the supplied circuit, and so connected that the current therein shall act on the field fiux so as either to oppose -or to assist the normal fiux, under conditions hereina-fter set forth. This series winding may be, on one or more main poles, or on interpoles, depending on the type of variable speed machine to which the invention is applied. I further provide means whereby this series winding may be short-circuited either wholly or in part or in Sections. Such means may consist of any known form of electro-magnetic switch or switches designed to operate at predetermined voltages.v so as to close or open the said short-Circuit or short-circuits.

My invention is applicable to variable speed dynamos of all classes, either with i Specification of LetterslPatent.

Application filed January 23, 1915.

Patented Nov. 5, 1918.,

Serial No. 3,926.

or without subsidiary brushes or shortcircuited brushes, or to such dynamos already provided With a reverse compound winding and either With or without Wound or unwound interpoles, or in which 'the regulation for speed variations is due to -arinature reactions, and to all known forms of variable speed dynamos in general.

An example of one type of variable speed dynamo to which my invention is applicable is described in the specification of my British Patent No, 9,655 of 1905, and in order that my invention may be fully understood l will describe its application to this type of machine by reference to Figures 1 to 4 of the accompanying diagrammatic drawings, in which I Fig. 1 is a view showing one arrangement vof such a dynamo provided with an additional series field Winding, andan electromagnetic device fort opening or closing a short-Circuit on the same.

Figs. 2 and 3 illustrate two modifications ofthe arrangement, and

4 illustrates a further application of my invention.

Referring first to the arrangement illustrated in Fig. 1, A is a `dynamo having a shunt field circuit B excited from a main brush C, and one subsidiary brush D. E is the battery of accumulators, F represents the lamps in the supplied circuit, and G an electro-magnetic cut-in and cut-out device of the well known type for making and breaking thel circuit of the dynamoA with the battery E and lamps F. i ii a is the reverse series winding in the field of said device across the main brushes C and C1 of the dynamo, the connection being made preferably through a contact d on the automatic cut-in andcut-out device G. The electro-magnet or solenoid coil c has an armature or core c and a short-circuiting bar f which, when in its normal position, serves to close two contacts g, h whereby the series field winding a of the'dynamo A is shortcircuited. The electro-magnetic device is calibrated by means of a spring or otherwise, or it may act by gravity, so that at a predetermined voltage the armature or core e is attracted, the short-circuit-bar f lifted, and

` the short-circuit thereby removed from the t'ermed a short shunt, but in some cases itJ is advantageous to connect it as a long shunt, that is to say, that one end, instead of being connected directly to the main brush C, would be connected to the farther side of the series winding a. Such an arrangement is disclosed in lFig. 3 when the lamp switch H is in its dotted line position as hereinafter described.

The subsidiary brush dynamo shown in Fig. 1 is given in'its simplest form by way of illustration merely. 'The invention is applicable, however, to all known forms of such dynamos whether with or without additional windings, or with or without interpoles.

Instead of inserting the series field winding in the dynamo circuit to both battery and lamps as shown in Fig. 1, I may insert 'it in the battery circuit only. ,Such an arrangement is shown in Fig. 2 where the series winding a will be seen to be in the branch circuit from the dynamo to the battery E, but not in circuit between the .dynamo and the lamps F.

With the arrangement of the circuits as shown in Fig. 2 it will be seen that when the lampsA are switched on, and the short-circuit is removed'from the series field winding a, a condition of things may be established in which the battery may be made to float; any increase in the voltage of the dynamo, tending to cause a charging current to pass into the battery, being immediately checked by the reverse current in the series winding a, while any tendency of the battery to discharge will cause a direct current in the series winding which will immediately boost up the voltage of the dynamo.

The automatic cut-in and cut-out device G `may in some cases as shown in Fig.` '2 be provided with a -pair of contacts Z, m which, when the device is in the4 off position, serve to short-circuit the series windin a when the lamps are on, but not when t ey are fof, and for this purpose the shortcirculting circuit may be interconnected with the lamp switch H.

Referring now to Fig. 3, this shows an arrangement of circuits in which the series windmg a is employed partly in a direct sense and partly in a reverse sense, that is to say, at one time to assist the normal field fiux, and at another time to oppose it. This 'is effected in the following manner:-

One of themain brushes of the dynamo A, say the posltive brush C, is connected in the first instance to the main lamp switch H which, when in the 011,7 position, enables the current to pass through the contact z' to the battery E, and through a branch circuit to the series winding a, and thence through the eontaetk of the lamp switch to the lamp circuit. Any discharge from the battery to the lamps will be in the same direction as the dynamo current through the series winding a, and this direction is direct, that is to say, it assists the normal field fiux, and increascs the excitation in proportion to the lampload. If, now, the lamp switch be p'lalced in the ofl` position, the positive dynamo brush C is disconnected from the contact i and connected to the contact j, and the contact which was formerly on 78 is remored therefrom. By this movement the lamp circuit is opened, and the current from the dynamo to the battery passes in a reverse direction through the series winding a, thereby limiting the output of the dynamo, and checking any tendency for the current to rise above the predetermined limit.

The series winding may be short-circuited by means of an electro-magnetic switch Z),

rent with a further rise of voltage, a secondl electro-magnetic switch 'n may be employed, calibrated for the higher voltage. switch may remove a short-circuit from a resistance 0 placed in the shunt field circuit of the dynamo, or in any circuit the insertion of resistance in which, or the modifying of which, will limit the output of the dynamo, such limit-ation being now sufiicient to reduce the output practically to zero, or thereabout, since the battery is now fully charged. This switch may advantageously be energized only when the first switch Z) has operated, as, for example, through the contacts p, g'.

In some cases it is advisable when the lamps are on to permit of the second electro-magnetic switch n Operating simultaneously with the first switch b. This may be accomplished, for example, by inserting a rcsistance 1' in series with the winding of the swltch, so that when th 1s resistance 1s shortclrculted the switch will act more strongly and, therefore, at a lower` voltage, c., at the.

predetermined voltage of the first switch, but if the resistance is not short-circuited it will not act until the higher predetermined volt- This' ularly resistance will prevent any Sudden rise of circuiting switches that, while they are cali-J brated to operate at predetermined voltages to remove the short-circuit, they shall not come off so as to renew the short-circmt except at very low voltages. This will prevent hunting of the automatic cut-in and cutout device due to the cutting-out speed o'f the dynamo being raised owing to a weakenedl field.

The series winding a, instead of being placed on the main poles as( shown in thevfigures of the drawings above described, may, in some classes of machines, be placed on subsidiary or interpoles, whether these poles have or have not other windings provided to compensate for speed variations. The present additional series winding will be superimposed upon any such speed regulation.

Fig. 4; gives, by way of example, an illustration of such an arra-ngement applied to a variable speed machine having the main fields excited by means of two subsidiary brushes, and the series winding placed upon unwound subsidiary or interpoles. A is the dynamo having two main brushes C and C1 and two subsidiarv brushes D' and D1, main p field coils B and B1, and a series winding a, a1 on subsidiary poles placed' between the main poles. Any of the auxiliary apparatus shown and described in the other drawings, or above referred to, may be used in this combination, and the series winding a, a1 is so arranged that when it is required to reduce the output of the machine, the current will pass in such a direction through it as to assist the cross-flux produced by the magnetization of the armaturetby armature current, as is well understood.

I do not confine myself to the particular arrangements shown in the accompanying drawings, which are merely diagrammatic and by way of example only. lIn particular, the electro-magnetic devices herein shown may be varied, modified, or combined in ways which will be obviousto those skilled in the art, as also will be the method of application of the invention to other types of variable speed machines than those particreferred to and illustrated in the drawings. i

Having now fully described and ascertained my said invention and the manner in which it is to be performed, I declare that what I claim is 1. The combination with a generator which is inherently self regulable for variations in speed, of an auxiliary series field superimposed upon the main field of said generator to ai/ford further regulation of said generator and means Sensitive to variations in the voltage of said generator to vary the effectiveness of said anxiliary field.

2. The combination with a generator which is inherently self regulable for variations in speed, of an auxiliary series field superimposed upon the main field of said generator to afiord further 'regulat-ion Vof -said generator, a storage battery to be supplied by said generator` and connections placing said auxiliary field in series between said generator and said battery to buck or boost the main field of said generator accordingly as the generator voltage or battery voltage predominates.

3. The combination with a generator which is inherently self regulable for variations in speed, of an auxiliary series field superimposed upon the main field of said generator, elctro-responsive means included in circuit with said generator to vary the effectiveness of said auxiliary field and means controlling said auxiliary field to utilizethe same for alternatively bucking'or boosting the main field of said generator.

4. The combination with a generator which is inherently self regulable for variations in speed, of a superimposed auxiliary series field thereof,'electro-responsive means associated with said generator to vary the efiectiveness of said auxiliary field for regulation of said generator, lamps and a battery to be supplied by said generator and circuit controllino' means for said auxiliary field, lamps and abattery to efl'ect reversals of the flow of current through said auxiliary field for boosting and bucking the main field of said generator under diflerent conditions.

5. The combination with a generator which is inherently self regulable for variations in speed, of a superimposed auxiliary series field therefor, electro-responsive means associated with said generator to vary the eifectiveness of said auxiliary field for regulation of said generator, lamps and a'battery to be supplied by said generator and circuit controlling means for said auxiliary field, lamps and battery to direct the current /fiow through said auxililary field for boostefiectiveness of said auxiliary field, lamps' and a battery to be supplied by said generator, and means for connecting said auxiliary field between battery and lamps for boosting relation with respect to the main field of said generator and for connecting said auxiliary field between said generator and said battery and reversing the relation of said auxiliary field with respect to the main field of said generator, when said lamps are disconnected.

7. In combination, a Variable speed gen-l said circuit and means for lacing said 15 winding in the lamp branch o said circuit to receive a uni-directional flow of current from said generator and said battery and to alternatively place said winding between said generator and said battery for reversal 20 of the current flow thereto from said generator while maintaining the same relation between said winding and said battery.

HENRY LEITNER.

Witnesses: C. G. REAPIN,

JOHN E. BoUsFIELD. 

